Balloon-expandable heart valve system and method of implantation

ABSTRACT

A system has a heart valve assembly that includes a stent-frame having an anchoring section and an outflow section, with the anchoring section having a distal annulus section and a support section that is positioned between the distal annulus section and the outflow section. The distal annulus section has a concave inflection. A leaflet assembly is stitched to the anchoring section. The system also includes a balloon on which the heart valve assembly is crimped, the balloon having a central valve contact portion that has an outflow portion, a neck portion, and a central portion between the outflow portion, and the neck portion. The outflow portion of the balloon receives the outflow section of the stent-frame, the central portion of the contact portion of the balloon receives the support section of the stent-frame, and the neck portion receives the annulus section of the stent-frame.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention is directed to systems for implanting expandableprosthetic heart valves and, in particular, a prosthetic heart valve anda shaped expansion member for deploying the heart valve.

2. Description of the Prior Art

Minimally-invasive heart valve replacement has become very common inrecent times. Such minimally-invasive heart valve replacement typicallyinvolve a self-expandable or a balloon-expandable stent integrated witha bioprosthetic valve having flexible leaflets, with the stent-valvedevice deployed across the native diseased valve to permanently hold thevalve open, thereby alleviating a need to excise the native valve. Thesedevices are designed for percutaneous delivery in a cardiaccatheterization laboratory under local anesthesia using fluoroscopicguidance, thereby avoiding general anesthesia and open-heart surgery.

These expandable heart valves use either balloon- or self-expandingstents as anchors. The uniformity of contact between the expandablevalve and surrounding annulus, with or without leaflets, should be suchthat no paravalvular leakage (PVL) occurs, and therefore properexpansion is very important. Perhaps more problematic is the quality ofcoaptation of the leaflets once the valve is expanded into place.Coaptation refers to the degree that the individual flexible leafletscome together in the valve orifice to occlude the back flow. If theleaflets do not quite meet, which could happen if the flexible valve isnot expanded properly, regurgitation may occur. These and other issuesmake proper implant of the valve extremely critical. However, unlikeopen-heart surgery, the implant site is not directly accessible orvisible and the valve must be implanted remotely at the end of acatheter or cannula under indirect visualization (e.g., fluoroscopicimaging).

Balloon-expandable heart valves typically require expansion with acylindrical balloon of clear nylon. The inflation fluid consists ofsaline mixed with a more viscous contrast media. The inherent viscosityof the mixture increases the inflation/deflation time, which isundesirable because the balloon occludes the target annulus when in use,and more and more procedures are being done off-pump, or on a beatingheart.

In addition, PVL remains as one of the major issues post transcathetervalve implant. Various designs have been developed but have proven to beunable to eliminate PVL.

Thus, there is a need for implantation systems and techniques thatreduce the time for and increase the chances of a successful implant,while minimizing or eliminating PVL.

SUMMARY OF THE DISCLOSURE

The present invention provides a system and method for deployingballoon-expandable prosthetic heart valves so that they assume theirdesired operational shape. The system includes a prosthetic heart valveand an expansion member that accommodates non-uniform expansionresistance in the heart valve to expand to its desired tubular or othershape.

The prosthetic heart valve assembly according to the present inventionprovides an outflow (aortic) end of the stent-frame that is slightlylarger than that of the inflow (ventricular) end. This design canmaximize the valve geographic effective orifice area (EOA) and reducethe stagnant blood near the cupid area during the diastolic cardiacphase when the valve is closed. This design can also reduce the risk ofpatient prosthetic mismatch due to the increase in EOA and can alsoreduce the valve related thrombosis.

To accomplish the objectives of the present invention, there is provideda system that has a heart valve assembly that includes a stent-framehaving an anchoring section and an outflow section, with the anchoringsection having a distal annulus section and a support section that ispositioned between the distal annulus section and the outflow section.The distal annulus section is defined by a single distal row of cellsthat has a distal-most annular ring of alternating peaks and valleys,with the distal row of cells having a concave inflection. A leafletassembly is stitched to the anchoring section. The system also includesa balloon on which the heart valve assembly is crimped, the balloonhaving a proximal section and a distal section, and a central valvecontact portion positioned between the proximal and distal sections. Thecontact portion has an outflow portion, a neck portion, and a centralportion between the outflow portion and the neck portion, and the neckportion has an inflection zone that corresponds in size and shape withthe concave inflection of the distal annulus section. The outflowportion of the balloon receives the outflow section of the stent-frame,the central portion of the contact portion of the balloon receives thesupport section of the stent-frame, and the neck portion receives theannulus section of the stent-frame.

The expansion member according to the present invention provides amechanism to restore the stent-frame into its initial-designed operatingshape by a unique balloon design. Specifically, the stent-frame ispre-set in a desirable geometry as mentioned above while the balloon isalso pre-set in a shape that is matched with the stent-frame. Therefore,during the deployment of the heart valve assembly, the stent-frame canbe restored in its preset shape when fully expanded.

The present invention provides a method for deploying the heart valveassembly using the expansion member or balloon of the present invention.The heart valve assembly is mounted on to the balloon in a manner wherethe outflow portion of the balloon receives the outflow section of thestent-frame, the central portion of the contact portion of the balloonreceives the support section of the stent-frame, and the neck portionreceives the annulus section of the stent-frame. The combined balloonand the mounted heart valve assembly are then delivered to the aorticannulus, and the balloon is expanded to cause the aortic annulus to bereceived inside the concave inflection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a heart valve assembly carried on anexpansion member according to one embodiment of the present inventionshown in an expanded configuration.

FIG. 2 is a side view of the assembly of FIG. 1.

FIG. 3 is a perspective view of the heart valve assembly of FIG. 1.

FIG. 4 is a side view of the heart valve assembly of FIG. 3.

FIG. 5 is a top view of the heart valve assembly of FIG. 3.

FIG. 6 is a perspective view of the stent frame of the heart valveassembly of FIG. 3.

FIG. 7 is a side view of the stent frame of FIG. 6.

FIG. 8 is a top view of the stent frame of FIG. 6.

FIG. 9 is a bottom view of the stent frame of FIG. 6.

FIG. 10 is an isolated front view of showing one column of the cells ofthe stent-frame of FIG. 6.

FIG. 11 is a side view of FIG. 10.

FIG. 12 is a perspective view of the leaflet assembly of the heart valveassembly of FIG. 3.

FIG. 13 is a side view of the leaflet assembly of FIG. 12.

FIG. 14 is a top view of the leaflet assembly of FIG. 12.

FIG. 15 is a bottom view of the leaflet assembly of FIG. 12.

FIGS. 16-19 illustrate the steps for delivering and deploying the heartvalve assembly of FIG. 3 at the aortic position of a human being.

FIG. 20 is a perspective view of the expansion member of FIG. 1.

FIG. 21 is a side view of the expansion member of FIG. 20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description is of the best presently contemplatedmodes of carrying out the invention. This description is not to be takenin a limiting sense, but is made merely for the purpose of illustratinggeneral principles of embodiments of the invention. The scope of theinvention is best defined by the appended claims.

The present invention provides an improved system and method fordeploying a balloon-expandable heart valve so that it can assume itsintended operating shape and better fits into a patient's aortic annulusand local anatomy. The designs in the present invention have twoadvantages in comparison to current balloon expandable transcather heartvalves (THVs). First, the super-annulus valve design increases thegeographic EOA of the valve and increases the space between thebioprosthetic leaflets and the stent-frame to reduce the stagnant bloodflow. Second, the unique stent-frame design at the inflow end provides abetter fit to the native aortic annulus, thereby reducing the risk ofPVL. The expandable heart valve assembly according to the presentinvention has a stent-frame that supports inner flexible leaflets thatprovide fluid occluding surfaces. The heart valve assembly is designedto expand from a compressed state for delivery into an operating shapethat ensures good coaptation of the leaflets.

The present invention described herein provides a solution that ensuresproper deployment of a balloon-expandable prosthetic heart valveassembly having a stent-frame that undergoes plastic deformation fromone size to a larger size. Examples of stent-frame materials include,but are not limited to, stainless steel, Elgiloy (an alloy primarilycomposed of cobalt, chromium and nickel), titanium alloys, and otherspecialty metals.

The present invention accommodates heart valves of non-constantexpansion resistance. That is, the balloon-expandable prosthetic heartvalve assembly has one end, typically the inflow end, that possesses agreater number of structural components, including stitching. The heartvalve assembly is mounted over an expansion balloon, delivered to theimplant site, and the balloon is inflated. Because of the axialconstructional non-uniformity of the heart valve assembly, expansion ofthe balloon will cause greater or earlier radial expansion at whicheverpart of the heart valve assembly presents the least expansionresistance. Typically, the inflow end presents greater resistance toexpansion, resulting in the outflow end experiencing greater and fasterexpansion. The present invention provides a unique balloon shape toaccommodate this constructional non-uniformity, so that the heart valveassembly expands to its designed operational shape. The final shape ofthe stent-frame can have a non-linear profile to adapt to the anatomy ofthe valve annulus.

FIGS. 1-2 illustrate a system 100 according to the present inventionthat includes a balloon-expandable prosthetic heart valve assembly 110carried on an expandable member 400 for deployment at a valve annuluslocation inside a patient, which in the present invention can be theaortic annulus. FIGS. 3-5 illustrate an exemplary balloon-expandableprosthetic heart valve assembly 110 having an inflow or distal end 112and an outflow or proximal end 114. The heart valve assembly 110includes an outer stent-frame 200 (see also FIGS. 6-11) supporting aleaflet assembly 300 (see also FIGS. 12-15). FIGS. 3-4 show the heartvalve assembly 110 in its expanded or operational shape, wherein thestent-frame 200 generally defines a tube and there are three leaflets306 attached thereto and extending into the cylindrical space definedwithin to coapt against one another. In the heart valve assembly 110,three separate leaflets 306 are part of the leaflet assembly 300 and areeach secured to the stent-frame 200 and to the other two leaflets alongtheir lines of juxtaposition, or commissures. Of course, a wholebioprosthetic valve such as a porcine valve could also be used. In thissense, “leaflets” means separate leaflets or the leaflets within anentire xenograft valve.

Referring to FIGS. 1-11, the stent-frame 200 has an anchoring section220 and an outflow section 230. The leaflet assembly 300 would besecured within the anchoring section 220. The anchoring section 220 hasa distal annulus section 222 and a support section 224. The entireanchoring section 220 is defined by a generally annular body having aplurality of four-sided or diamond-shaped cells 202. Each cell 202 isformed by four struts 211 connected at connection points or nodes 212.

The annulus section 222 is primarily defined by the distal-most row ofcells 209 that has a distal-most annular ring of alternating peaks 210and valleys 213. The row of cells 209 has a concave inflection 226, withthe row of peaks 210 having the greatest diameter and the row of valleys213 having the smallest diameter and being the innermost valley of theconcave inflection 226. Thus, the distal-most row of struts thatalternate between the peaks 210 and the valleys 213 are curved or bentinwardly until they reach the valleys 213 (which act as inflectionpoints), and then curve or bend outwardly towards the struts in thesupport section 224.

The support section 224 is defined by a plurality of rows (e.g., fourrows as shown in FIG. 7) of cells 202 that can have generally the samediameter throughout (and slightly tapered, as described below) so as tobe generally cylindrical. Each cell in the distal-most row of cells 202shares a common strut with one adjacent cell of the row of cells 209.The sizes and shapes of the cells 202 can be generally the same orconsistent throughout the support section 224, with the cells 209 beinggenerally larger than the cells 202. As a result, the annulus section222 is more flexible than the support section 224.

The proximal-most ring of cells 202 in the support section 224transitions to the outflow section 230. Each cell in the proximal-mostrow of cells 202 in the support section 224 shares a common strut withone adjacent cell of the row of cells 203 in the outflow section 230.The outflow section 230 is defined by a single row of cells 203, witheach cell 203 having a generally hexagonal shape defined by six struts.The outflow section 230 has a proximal-most annular ring of alternatingpeaks 205 and valleys 206 that are connected to each other by angledstruts 204, and the valleys 206 are connected via straight struts 201 tothe nodes 207 that connect the common struts that are shared by thecells in the proximal-most row of cells 202 in the support section 224.

The cells 203 are generally larger than the cells 202, and can also belarger than the cells 209.

FIGS. 10-11 are isolated views showing one column of the cells 209, 202and 203 of the stent-frame 200. As best shown in FIG. 11, the strutsthat define the cells 209, 202 and 203 are not straight, but are insteadslightly curved (i.e., have an arcuate shape), with the nodes 212 beinginflected or extending slightly inwardly. In addition, as shown in FIG.11, the overall diameter of the stent-frame 200 can gradually increasefrom the distal end of the support section 224 all the way to theproximal end of the outflow section 230 to form a very slight taper. Thestent-frame 200 can have its largest diameter along the ring of peaks210.

The shapes of the cells 203, 202 and 209 are provided for differentpurposes. For example, the hexagonal shape of the cells 203 is providedso that the cells 203 are more open for coronary access, and so that theoutflow section 230 can be more flexible for the balloon 400 to expand.The cells 209 are configured to allow the annulus section 222 to be moreflexible so that the inflow end 112 of the stent-frame 200 can be mademore flexible so that it would be easier to create a neck when theballoon 400 expands.

Referring now to FIGS. 12-15, the leaflet assembly 300 is illustrated ashaving three leaflets 306, although it is also possible to provide aleaflet assembly that has two or four leaflets. An annular skirt havinga plurality of skirt portions 307 supports the leaflets 306. In thisembodiment, one skirt portion 307 is provided for each leaflet 306, withsutures 311 connecting the leaflet 306 to the skirt portion 307. Sutures308 and 310 connect the adjacent edges of the skirt portion 307 to eachother to form the annular skirt. An annular distal (inflow) edge 309 isdefined by the skirt portions 307. Each leaflet 306 has two coaptationedges 301 that coapt with one coaption edge 301 from each of the othertwo leaflets 306, and each edge 301 has a skirt end 302 and an oppositecoaptation end that meet near a central coaptation location 303.

The leaflets 306 and the skirt can be made from any known material thatis commonly used for such leaflet assemblies, including porcine, bovine,or synthetic materials.

In the heart valve assembly 110, the flexible material forming theleaflets 306 attaches to the stent frame 200 via the skirt portions 307.Specifically, the skirt portions 307 are stitched or sutured to theanchoring section 220, and the skirt portions 307 extend throughout thedistal annulus section 222 and the support section 224. As best shown inFIGS. 3-4, the leaflets 306 extend from a proximal-most position at thenodes 207, and curve distally towards the center of the support section224. The skirt portions 307 extend from the peaks 210 proximally todifferent depths of the support section 224.

The bulk of the attachment structure between the stent-frame 200 and theleaflets 306 is located close to the inflow end 112. Each leaflet 306preferably connects along an arcuate line between two points near theoutflow end 114, and this arcuate line passes close to the inflow end112, and thus the need for more sutures and the inflow end 112. As aresult, the heart valve assembly 110 has a nonuniform expansion profile.More particularly, the inflow end 112 exerts substantially greaterresistance to expansion on a balloon inflated from within than theoutflow end 114. A cylindrical balloon inflated from within the heartvalve assembly 110 will therefore expand faster or farther at theoutflow end 114 than at the inflow end 112, because the outflow end 114presents the path of least resistance.

As mentioned above, the present invention provides differently-shapedexpansion members or balloons to ensure designed expansion of prostheticheart valves. As mentioned above, balloons are almost universally usedto deploy expandable heart valves. However, it is conceivable that amechanical expansion member such as elongated fingers or hydraulicallyoperated expanding members (i.e., not balloons) could be utilized.Therefore, the term “expansion members” is intended to encompassballoons and other variants.

In FIGS. 1-2 and 20-21, a balloon 400 mounts on a catheter and includesa proximal section 405, a central valve contact portion 420, and adistal section 406. The contact portion 420 includes an outflow portion430, and neck portion 422, and a central portion 424. The proximalsection 405 tapers with an increasing diameter distally from proximalend 407 to a first shoulder 440, which transitions into the outflowportion 430 at an annular transition line 404. The outflow portion 430is adapted to receive the outflow section 230 of the stent-frame 200,and can have a generally constant diameter. The central portion 424 isadapted to receive the support section 224 of the stent-frame 200, andcan be slightly tapered. The neck portion 422 is adapted to receive theannulus section 222 of the stent-frame 200, and is sized and shaped tomatch the size and shape of the intended annulus section 222. The neckportion 422 has an inflection zone 411 which is generally concave andwhich corresponds in size and shape to the concave inflection 226 on thestent-frame 200. The neck portion 422 the radially expands from theinflection zone 411 until it reaches a second shoulder 406 at an annulartransition line 403. The second shoulder 406 transitions into the distalsection 409, which gradually tapers in the distal direction towards adistal end 408. The balloon 400 can include a plurality of marker bands(not shown) therearound to facilitate registration of the heart valveassembly 110 with the balloon 400.

It is important to note that the terms “proximal and distal” in terms ofthe balloon is dependent on the direction of heart valve delivery intothe annulus, because the heart valve leading end and thus balloonorientation on the catheter will be reversed in a heart valvereplacement procedure that begins in a femoral artery as compared to aprocedure that enters through the apex of the left ventricle.

The heart valve assembly 110 described above is positioned in itsexpanded state around the deflated balloon 400. Marker bands (not shown)are well-known in the art, and can be used to position the heart valveassembly 110 axially on the balloon 400 for proper inflation. Because ofthe non-uniform expansion profile of the balloon 400, the axial positionof the heart valve assembly 110 is most important to ensure that theportions of the balloon 400 that are capable of applying the largestinitial radially outward force are in registry with the stiffer areas ofthe heart valve assembly 110. In particular, the heart valve assembly110 is positioned on the balloon 400 such that its inflow end 112 ispositioned on the neck portion 422, and its outflow end 114 ispositioned on the outflow portion 430. Subsequently, the heart valveassembly 110 is crimped around the balloon 400 so as to be ready fordelivery into the body and advancement to the target implantation site.When the balloon 400 inflates, the neck portion 422 initially expandsfaster and ultimately farther than the outflow portion 430, thuscompensating for the increased resistance to expansion of the heartvalve assembly 110 and its inflow end 112. By careful calculation of thenon-uniform resistance of the heart valve assembly 110 to expansion, theballoon 400 can be chosen so that the heart valve assembly 110 expandsto its full diameter and proper operational shape (typically a cylinderor a shallow frusto-conical shape).

As will be appreciated by those of skill in the art, the specific shapeof the expansion member/balloons described herein will differ dependingon the valve construction.

Conventional balloons used to deploy prosthetic heart valves are made ofclear nylon. Nylon balloons have a maximum expansion diameter which isimportant to avoid over-inflation and rupture. In addition, materialssuch as Pebax™ (polyether block amid) or PET (polyethyleneterephthalate) can also be used.

The balloon 400 can be made according to any one of different approachesalone or in combination. For example, the balloon 400 can be pre-shapedusing known techniques to the desired configuration and size in itsexpanded state. As another example, in U.S. Pat. No. 5,348,538,incorporated herein by reference, there is described a single layerballoon which follows a stepped compliance curve. The stepped compliancecurves of the balloon provide a lower pressure segment where the balloonrapidly expands yielding inelastically, and a higher pressure region inwhich the balloon expands along a generally linear, low compliancecurve.

Another approach to making the balloon 400 involves providingrestriction members along the outer surface of the balloon whichfunction to limit the expansion of the balloon at the location of theserestriction members.

Yet another set of approaches involve varying the stiffness orthicknesses of the balloon material. For example, different materialswith varying stiffness might be used to enhance the diameter at selectedportions of the balloon 400. Materials such as PET, nylon, PEBAX™ orother polymers have adaptable or selectable ranges of stiffness. In someembodiments, the balloon 400 can have a wall material that is relativelystiff under at the inflow end 112, and relatively soft under the outflowend 114. Alternatively, the thickness of the wall of selected portionscould be reduced to allow its expansion to the larger diameter. Anotherapproach would be to expand the balloon 400 into a heated die with thedesired end-shape. Yet another approach would be to apply coatings oradditional layers, such as flexible, knitted sleeves, at strategiclocations on the balloon's surfaces.

In addition, the balloon 400 can be doped with a radiopaque material.The doping is typically performed prior to balloon extrusion to ensureuniform distribution of the doping agent. Consequently, because theballoon itself is radiopaque, saline can be used to inflate it withoutaddition of a viscous contrast media. Because of the lower viscosity ofsaline, the inflation/deflation time is greatly reduced.

In a typical operational sequence, the heart valve assembly 110 can bepackaged in a separate sterile container from the balloon 400, or can bepre-crimped on the balloon 400 of a delivery catheter if dry tissuetechnology is used to treat the leaflets. In the operating room, theheart valve assembly 110 and balloon 400 are conjoined for implantation.This procedure requires careful positioning of the valve in its expandedstate around the balloon, and crimping of the valve onto the balloon toa predetermined maximum diameter. The marker bands described abovetherefore greatly facilitate the step of positioning the valve over theballoon to ensure proper expansion.

The combined heart valve assembly 110 and balloon 400 combination isthen inserted into the body and advanced to the target implantationsite. FIG. 16 shows access through the femoral artery and the ascendingaorta 504. As shown in FIG. 16, the balloon 400 is carried on the distalend of a delivery catheter, and the heart valve assembly 110 and balloon400 combination is delivered to the location of an aortic annulus 502between the natural aortic leaflets 503. FIG. 17 shows the balloon 400being expanded so that the heart valve assembly 110 also expands. FIG.18 shows the heart valve assembly 110 fully expanded at the location ofthe annulus 502. At this position, the expanding distal end of the neckportion 422 (which carries the annulus section 222 of the stent-frame200), as well as the distal section 406, of the balloon 400 extend intothe left ventricle 501. The balloon 400 is then deflated and withdrawn(see FIG. 19). As shown in FIGS. 18 and 19, the annulus 502 is receivedinside the concave inflection 226 of the stent-frame 200, therebysecuring the heart valve assembly 110 at the location of the aorticannulus 502.

As best shown in FIGS. 18-19, the heart valve assembly 110 is sized andshaped to be securely deployed at the aortic annulus 502 in a mannerwhich reduces or minimizes PVL and maximizes the valve geographic EOAwhile reducing the stagnant blood near the cupid area during thediastolic cardiac phase when the valve leaflets 306 are closed. Inaddition, the balloon 400 is shaped to facilitate the delivery,expansion and implantation of the heart valve assembly 110.

While the description above refers to particular embodiments of thepresent invention, it will be understood that many modifications may bemade without departing from the spirit thereof. The accompanying claimsare intended to cover such modifications as would fall within the truescope and spirit of the present invention.

What is claimed is:
 1. A system, comprising: a heart valve assembly,comprising: a stent-frame comprising an anchoring section and an outflowsection, the anchoring section having a distal annulus section and asupport section that is positioned between the distal annulus sectionand the outflow section, wherein the distal annulus section is definedby a single distal row of cells that has a distal-most annular ring ofalternating peaks and valleys, with the distal row of cells having aconcave inflection, wherein the outflow section is defined by a singleproximal row of cells, with each cell in the proximal row of cellshaving a generally hexagonal shape, and having a proximal-most annularring of alternating peaks and valleys, and a leaflet assembly stitchedto the anchoring section; and a balloon on which the heart valveassembly is crimped, the balloon comprising: a proximal section and adistal section; and a central valve contact portion positioned betweenthe proximal and distal sections, the contact portion having an outflowportion, a neck portion, and a central portion between the outflowportion and the neck portion, wherein the neck portion has an inflectionzone that corresponds in size and shape with the concave inflection ofthe distal annulus section; and wherein the outflow portion of theballoon receives the outflow section of the stent-frame, the centralportion of the contact portion of the balloon receives the supportsection of the stent-frame, and the neck portion receives the annulussection of the stent-frame.
 2. The system of claim 1, wherein the entiresupport section is defined by a generally annular body having aplurality of four-sided cells.
 3. The system of claim 2, wherein eachcell in the single distal row of cells is four-sided.
 4. The system ofclaim 1, wherein the alternating peaks and valleys of the proximal-mostannular ring are connected to each other by angled struts, and eachvalley has a straight strut extending therefrom to connect to thesupport section.
 5. The system of claim 1, wherein the distal-mostannular ring of alternating peaks and valleys defines a ring of distalpeaks that has a distal peak diameter and a ring of distal valleys thathas a distal valley diameter, with the distal peak diameter having thegreatest diameter for the entire stent-frame, and the distal valleydiameter having the smallest diameter for the entire stent-frame.
 6. Thesystem of claim 1, wherein the distal annulus section is more flexiblethan the support section.
 7. The system of claim 1, wherein the outflowsection is more flexible than the support section.
 8. The system ofclaim 1, wherein the outflow section is more flexible than the distalannulus section.
 9. The system of claim 1, wherein the support sectionhas a tapered configuration.
 10. The system of claim 1, wherein theballoon has a varying diameter which is smallest at the inflection zone.11. The system of claim 1, wherein the contact portion of the balloonhas a tapered configuration.
 12. A method for deploying a prostheticheart valve at an aortic annulus of a patient's heart, system,comprising: providing a system comprising: a heart valve assembly,comprising: a stent-frame comprising an anchoring section and an outflowsection, the anchoring section having a distal annulus section and asupport section that is positioned between the distal annulus sectionand the outflow section, wherein the distal annulus section is definedby a single distal row of cells that has a distal-most annular ring ofalternating peaks and valleys, with the distal row of cells having aconcave inflection, wherein the outflow section is defined by a singleproximal row of cells, with each cell in the proximal row of cellshaving a generally hexagonal shape, and having a proximal-most annularring of alternating peaks and valleys, and a leaflet assembly stitchedto the anchoring section; and a balloon on which the heart valveassembly is crimped, the balloon comprising: a proximal section and adistal section; and a central valve contact portion positioned betweenthe proximal and distal sections, the contact portion having an outflowportion, a neck portion, and a central portion between the outflowportion and the neck portion, wherein the neck portion has an inflectionzone that corresponds in size and shape with the concave inflection ofthe distal annulus section; mounting the heart valve assembly on to theballoon in a manner where the outflow portion of the balloon receivesthe outflow section of the stent-frame, the central portion of thecontact portion of the balloon receives the support section of thestent-frame, and the neck portion receives the annulus section of thestent-frame; delivering the balloon and the mounted heart valve assemblyto the aortic annulus; and expanding the balloon to cause the aorticannulus to be received inside the concave inflection.